Distance measuring apparatus



Sept. 2, 1958A M. M. MALEC l l l 29,849,800

DISTANCE MEASURING APPARATUS Filed may 5, 1955" Abear against the twoslides by meansvof knife-edges. these ,embodiments `any lateral movementlof the slides lcauses an error inmeasurementgit followsthat theipre-`cision of the apparatusds.reducedbyany irregularity in manufacture,particularlyby any difference in-the diameter of the balls or rollers cnwhich the said slides move.

United States Patent@ My invention-relates to improvements"inprecision,mea uring apparatus such as comparators, referencegauges,

,calipersnand other similar,instruments,vof the type in lwhich themovement ofthe gauging finger istransmitted to indicating membersby.kinematicdisplacement amplifiers.

I t hasv already been proposed to. transmit the movement of the gaugingfinger to the indicating member or mem- .bers through bearing meanscomprising, in particular,

slides and rollers, the indicating members or index being ,keyed onthelast rollers to receive lthe movement or on intermediatemembers.

More especially,it,has been proposed-,togrip the roller orrollers.or.need1es,carrying the .indicatingmembers, or index, betweentwoslides moving,in yopposite directions .andgpulled orpushed towards eachother by resiliently deformable means and guidedby balls orrollers, oneof the slides being subjected .tothe naction cfa ,drawback v spring andthevotherfbeing connected vto the gaugingnger.

",In certainembodiments of this type of apparatus a kinematic connectionis provided,betwe en the slides by meansvof a beam of which the centrebears,a gainst an intermediate knife-edge, the beam also bein'glmade VtoIn It is among theonbjects ofthe invention to provide an 4apparatus ofthis typeinwhichny laterahdisplacement of the slides has no effectwhateveron rthe precision of measurement and to ensure a constant,predetermined pressure .of,applicat ion,\v prefergablyf,fadjustable, ofone slide against thel other, ywhatever may beV the respective positionsof the two slides.

`It isA another. object ofthe. invention-to providea'special rdevicebetween the. gauging, finger orthe rod directly con- .nected to .thefingenand. that one of: the two `slides which .is not directlysubjectedto, the -actionof ,a drawback-spring,

the said device beingsoarranged .that all the parts are kept in contactand the play is automatically taken up, whereby normal operation` ofthe-machine Yis ensured, Iwhatevermay-betheeforce broughtto bearon'thegauging finger.

These and other objects and advantages of the invention will be apparentto those skilled in the art from a consideration of the followingdetailed description in conjunction with the accompanying drawings inwhich:

Fig. 1 is a front view, in diametral section, of a specimen embodimentof a measuring apparatus with slides, the gauging finger being out;

Fig. 2 is a cross-section along the line II-ll of Fig. l;

Fig. 3 is a cross-section along the line lll-IH of Fig. 1; and

Fig. 4 is a partial view showing the arms of the shockabsorbin-g devicein the open position brought about `by the sudden exercise of force onthe gauging nger.

Patented Sept. 2f, 1958 ICC In the specimen'embodimentfshown inFigs. 1vto 4, the measuringapparatus as a 'general casing-l-inside which arehoused,fin particular, -a baselplate 2serving to1 vguide a rod3^of-which the'out-side end istitted with a'gauging finger. On asupporting Vpart'S fixed to thecasing 1 and a horizontally movablevpart: 6, balls 9,10 run, which in this instance are; held in cages 7,8,a race11,'12 respectively `being machined on the corresponding vsurlfaceoftherpart'spSy to guide theballs -9,10. lr)The part 5 isxed tothe'platensl13,i14andithe other part-6,

is adjusted between" the two -platens *in ysuch afway' as to be able to'slide' horizontallyfand i-ssresiliently rurged towards the other 'part'5,'1bya spring 1'5l xed to'ethe base Lplate 2 andprovided-withatightening screw116. Between'theball'cages 7 and'S-are-mounted-twoslides 17, 18 which can move in translation-parallel"to^the plane of theAsurfaces "of the Yparts `5, 6, and whichl have said slides 17, 18 nothaving"A any contact withi-the front kplaten-14 `and rearplaten13Kinematic connectionbetween the -slides17 and 18 is made byianVarm 21 swivelling roundl a fixed shaft`2,2f`1tted1atitsendsHwith-twotsmall identical rollers 23,"24symmetrical in relation to the vshaft l22, which rollersco-operateqwithplane and'parallel contact surfaces "25 and '26vrespectively, lprovided 4on the slides -17 and-'18 so that the slidesmust necessarily executive a movement Vof translationin oppositedirections.--Between'thetwo slides117-and18are tightly held twoperfectly Around 4needles27, 28, the shaft -'ends `of which fit intohorizontal grooves inthe platensiofthe apparatus. The slide 17 isconstantly-subjectedto the action of a restoringforce'throughanarrn^29-mounted so as to swivel round the spindle30 integral with theend of a spiral spring. Thefend of -the arm g29 carries a yroller 31which pushes vagainst a plane surfaced-the slide 17. TheV slide 18 has a`tail`32 with aA plane "end l33connected to the planefend 34 of the rod3fthrough a system of'levers constitutedeby `a'swivelling arm 35 mountedon a lshaft 36v the end of which'carriesa roller 37 co-operating withthe plane end 34 of the rod v3'Yand urged towards the saidrodby-a'spiralispring 438 ofegreater strength `than theA spiralspringmounteda onthe shaft-30.

kThisarm -35 isa U-'section memberinsidewhich a'second swivelling arm 39canmove, thevsaidarm being-also mountedonv the shaft36gandfbeingconstituted also by a U-sectionmemberthe Iconcavityfof`which is turned toward that ,of -the U-sectiou'member 3S-and which canpushagainsty it. VThe endgof the arm `39 carries a roller '40co-operatingvwith the-planesurface 33 of the slide318.

the action ofthe-spring @38,tholdsvtheroller '37 in contact with the end34 of the rod 3 and, flattening the spring 41, causes the arm 39 to bearagainst the plane end 33 of the tail 32 of the slide 18, through itsroller 40. The slide 18 is raised and consequently the slide 17 islowered and the arm 29 is forced downwardly against the action of thedrum spring fitted on the shaft 30, the force of which is less than thatof the spring 38. When the gauging finger and its rod 3 are pressed into measure a thickness, the arm 35 swivels clockwise round its shaft 36.But the action of the spring fitted on the shaft 30 makes the arm 29swivel clockwise, and this movement is transmitted by the roller 31 tothe slide 17 which undergoes a vertical translational movement upwardson the balls 9. This movement, in turn, is positively transmitted to theslide 1S by the roller 23 of the arm 21, which swivels round the shaft22 and by the roller 24 bearing downwardly on the slide 1S. The actionof the tail 32 on the roller 40 holds the arm 39 in place against thearm 35, overcoming the tension of the `spring 41. It is therefore seenthat any normal displacement of the gauging iinger While a measurementis being taken brings about two translational movements, in oppositedirections but of the same magnitude, of the two slides 17 and 13, andtherefore a rotation without slip of the needle 27 round its axis, whichremains fixed in space, the said needle being held tightly between thetwo slides with a predetermined, adjustable and constant pressure, dueto the provision of the balls 9 and 1t) on either side and of theadjustable spring 15. A brake can be provided on the shaft of the secondneedle 28, so as to avoid any sudden and unexpected movements of themoving members of the apparatus.

If a sudden force is exerted on the gauging finger, it

simply causes the arm 35 to rotate rapidly clockwise about the shaft 35and the angle formed by the arm 36 and the arm 39 to open under urgingof the spring 41, without the said force being transmitted to the othermembers of the apparatus and being likely to damage it.

Although there is described but a single embodiment of this invention,it will be obvious to those skilled in the art that various modicationsmay be made in the details of construction without departing from theprinciples herein set forth. features of the invention may be omitted inany given construction without altering the other desirable features.

What I claim is:

1. In a measuring instrument of the type wherein translational movementof an input member is converted into rotational movement of an index thecombination comprising a framework, a pair of slides supported on saidframework for translational movement in opposite directions alongparallel paths, the two slides having mutually opposed, spaced-apartplane surfaces, a pair of slotted bearings on said framework the axiswhereof is normal to said paths, a spindle rotatably supported in saidbearings interposed between said surfaces and frictionally grippedtherebetween whereby movement of said from said first spindle, mean-sfor biasing at least one of said slides in a direction normal to saidpaths to provide rolling friction on said spindles, an index carried onsaid first spindle, a pivoted rocker at one common end of said slidesand having a roller at each extremity thereof abutting said ends fortransmitting translational movement of either slide to the other, asecond rocker positioned adjacent the other common end of said slides,one extremity of said second rocker having a roller abutting the inputmember and the other extremity thereof having a roller abutting saidsecond common end of one of said slides, bias means for maintainingabutment of the rollers of said second rocker, a pivoted arm having aroller It will be further obvious that certain 7 at its distal endabutting the said second common end of said other slide, bias means formaintaining abutment of said last roller, the axes of the said tworockers and said arm being parallel to each other and normal to thedirection of translational movement of the slides, the areas of abutmentof the slides with their respective rollers being plane surfacesparallel to said axes, and the pivotal axis of said rst rocker beingequidistant from the points of abutment of said first rocker rollers. A

2. The combination in accordance with claim l wherein said second rockercomprises two parts, one constituting one leg of the rocker and theother part constituting the other leg thereof, said legs beingindependently pivoted on the axis of the rocker, spring meansinterconnecting said parts having a spring constant such, that duringnormal operation of the instrument, the rollers of said second rockerarm are maintained in their abutting relation and whereby, uponapplication of abnormal force to the input member said parts mayindependently pivot to relieve the slides of shock.

3. In a measuring instrument of the type wherein translational movementof an input member is converted into rotational movement of an index thecombination comprising a framework, a pair of slides supported on saidframework for translational movement in opposite directions alongparallel paths, the two slides having mutually opposed, spaced-apartplane surfaces, a pair of slotted bearings on said framework the axiswhereof is normal to said paths, a spindle rotatably supported in saidbearings interposed between said surfaces and frictionally grippedtherebetween whereby movement of said slides is converted into rotationof said spindle, a second pair of slotted bearings, an idler spindlerotatably supported in said second bearings and also frictionally heldbetween said surfaces, said idlervspindle being spaced from said rstspindle, eans for biasing at least one of said slides in a directionnormal to said paths to provide rolling friction on said spindles, anindex carried on said first spindle7 a pivoted rocker at one common endof said slides and having a roller at each extremity thereof abuttingsaid ends for transmitting translational movement of either slide to theother, means for connecting the input member to one of said slides, biasmeans for maintaining said slides and rollers in abutment, therespective axes of said rollers being parallel to each other and bothnormal to the direction of translational movement of the slides, thesurfaces of said slides upon which said rollers abut being plane andparallel to the pivotal axis of said rocker and said axis beingequidistant from the lines of abutment of said rollers.

References Cited in the rile of this patent UNITED STATES PATENTS1,006,924 Erb Oct. 24, 1911 1,729,466 Whittemore Sept. 24, 19291,842,502 Blomquist Jan. 26, 1932 2,493,313 Rabe Jan. 3, 1950 FOREIGNPATENTS 732,515 Germany Mar. 4, 1943 642,723 Great Britain Sept. 13,1950 976,052 France Oct. 25, 1950

